[p4] Race condition with p4 counters

[Rick Macdonald]

Two years ago I submitted a suggestion to have an atomic 
"get-next-value" for counters. They replied that they are considering it 
for the future and added my name to the list of people who have asked 
for this. As far as I can see, it has not been done.

In the shower this morning, I came up with this idea, which surely must 
be done atomically within the Perforce server:

$ p4 job -o | sed -e 's/<enter description here>/Temporary job to get 
next Job counter and increment it./' | p4 job -i
Job job000007 saved.
(parse the message above to get the job number)
$ p4 job -d job000007

I think this will work for me. I don't care about monotonically 
increasing numbers for anything that I need these counters for 
(including Jobs, because I'll use a different prefix anyway). It's three 
p4 command executions, but we'd only do this a few times a day.

Has anybody found a better idea?

Here is an unsupported script that Perforce send me, but I think it 
still suffers from a race condition. Am I wrong?

import os, time
 
        # wait for foolock counter to be set to zero
        # if it times out, just go ahead and grab the lock
        timeout = 4
        while int(os.popen('p4 counter foolock').read()) != 0 and 
timeout>0:
          print 'attempting to get lock...'
          timeout = timeout - 1
          time.sleep(1)
        if timeout == 0: print 'breaking lock'
 
        # grab lock
        os.popen('p4 counter foolock 1')
        if not int(os.popen('p4 counter foolock').read()) == 1:
          raise 'unable to obtain lock!'
 
        # get and increment foo counter
        foo = int(os.popen('p4 counter foo').read()) + 1
        os.popen('p4 counter foo %d' % foo)
        if not int(os.popen('p4 counter foo').read()) == foo:
          raise 'unable to set foo counter!'
 
        # release lock
        os.popen('p4 counter -d foolock')
        if not int(os.popen('p4 counter foolock').read()) == 0:
          raise 'unable to release lock!'